Combining electrocoagulation process using aluminum electrodes with activated carbon on the removal of humic acid from synthetic and industrial wastewater

Combining electrocoagulation(EC) with activated carbon(AC) represents a synergistic approach for water treatment, leveraging the unique advantages of both technologies. EC involves the use of an electric current to destabilize and aggregate contaminants, facilitating their removal through the formation of coagulated flocs. By integrating AC into the treatment process, the adsorption capacity of the system is enhanced. The presence of humic acid (HA) in water has raised significant apprehensions due to its toxicity and its capacity to give rise to carcinogenic trihalomethanes. This study investigates the Combining EC process using aluminum electrodes with AC on the elimination of HA from synthetic and industrial wastewater. The main effect of EC parameters and combination with adsorption on AC to remove humic acid was evaluated by Response Surface Methodology using a Box-behnken Design. The characteristics of the produced sludge were investigated to understand the behaviour of HA during treatment. A quadratic model was used to predict removal rates, significance and interactions with independent variables were assessed by analysis of variance (ANOVA). Under conditions involving 100 mg of Na₂SO₄ and an electrical current of 0.07 A, raising the AC mass to 0.3 g/L boosts the HA removal efficiency to 99.76%. However, when these parameters are evaluated using software Statgraphic, the results indicate that the optimal conditions for HA removal are a pH of 4, a current intensity of 0.075 A, a Na₂SO₄ concentration of 100 mg/L, an activated carbon dosage of 0.15 g/L, and an electrolysis duration of 10 min. Under optimal operating conditions, the process attained close to complete elimination (99.84%) with minimal treatment duration, energy consumption and cost overheads.